A polysilicon-insulator-polysilicon (PIP) capacitor uses polysilicon as a capacitor electrode. The PIP capacitor has a limit in reducing resistance of the capacitor electrode due to characteristics of the polysilicon.
When a bias voltage is applied to the polysilicon capacitor electrode, a depletion region is generated and voltage is thus unstable, and as a result, a capacity of the capacitor is not constantly maintained.
Therefore, research into the MIM capacitor is actively progressed. The MIM capacitor has a structure in which a dielectric layer is arranged between upper and lower metallic electrodes.